Effect of steady hypothermia and normothermia on multimodality evoked potentials in human poikilothermia.

OBJECTIVE: To assess the effects of steady-state spontaneous hypothermia on multimodality evoked potentials and on peripheral nerve conduction in human poikilothermia. DESIGN AND SETTING: Case series at a university hospital. PATIENTS: Four patients (four women, aged 28 to 37 years) with acquired poikilothermia. MAIN OUTCOME MEASURES: Short-latency somatosensory, brain-stem auditory, and visual evoked potentials as well as motor and sensory peripheral nerve conduction velocity during steady-state spontaneous hypothermia and normothermia. RESULTS: The marked latency prolongation of all evoked potentials and decreased peripheral nerve conduction velocity observed during steady-state spontaneous hypothermia (mean +/- SD core temperature, 33.5 +/- 0.3 degrees C) compared with normothermia (36.9 +/- 0.4 degrees C) agrees with previous findings during short-term induced hypothermia. CONCLUSIONS: The unequivocal effect of sustained mild spontaneous hypothermia on evoked potentials and peripheral nerve conduction velocity underlines the importance of meticulous attention to even small alterations in core temperature in interpreting neurophysiological investigations.

Cobalamin supplementation improves cognitive and cerebral function in older, cobalamin-deficient persons.

BACKGROUND: Mild cobalamin (Cbl) deficiency is frequently found in older persons and is associated with cognitive and cerebral abnormalities. The effects of Cbl supplementation on these abnormalities are largely unknown. METHODS: In a single-blind, placebo-controlled intervention study, 16 healthy community-dwelling elderly subjects with low plasma Cbl concentration and no cognitive impairments were studied. Subjects underwent 1 month of treatment with placebo, followed by 5 months of treatment with intramuscular injections of hydroxycobalamin. Before and after measurements of plasma cobalamin, total homocysteine (tHcy), methylmalonic acid (MMA), quantitative electroencephalograph (qEEG), and psychometric tests were taken. RESULTS: After Cbl supplementation, plasma Cbl concentrations increased, and plasma MMA and tHcy concentrations decreased. The performance on the Verbal Word Learning Test, Verbal Fluency and Similarities improved. qEEG showed more fast activity and less slow activity. Lower plasma tHcy concentrations were related to increased fast activity on qEEG on the one hand and improved performance on the Verbal Word Learning Test and Similarities on the other. Increased fast or decreased slow activity on qEEG was associated with improved performance on the Verbal Word Learning Test, Similarities and Verbal Fluency. CONCLUSIONS: Electrographic signs of improved cerebral function and improved cognitive function were found after Cbl supplementation in older subjects with low plasma Cbl concentrations who were free of significant cognitive impairment. These improvements were related to a reduction of plasma tHcy concentration.

Neurophysiological studies in the Leigh syndrome.

We performed neurophysiological studies in 12 patients with the Leigh syndrome (6 pathologically confirmed and 6 clinically diagnosed). The results are compared with data derived from a literature survey of 173 Leigh syndrome patients. We found no positive contribution of neurophysiological studies towards the diagnosis of the Leigh syndrome.

Effect of thymectomy on myasthenia gravis and autoimmune thrombocytopenic purpura in a 13-year-old girl.

We report the association of myasthenia gravis (MG) and autoimmune thrombocytopenic purpura (AITP) in a 13-year-old girl. The co-existence of these autoimmune diseases is rare in adults and, to our knowledge, never described in children. In our patient thymectomy had a therapeutic effect on both MG and AITP, suggesting a altered T-cell function as a pathogenic factor of major importance in both affections.